Enum sequoia_openpgp::crypto::S2K

#[non_exhaustive]
pub enum S2K {
    Iterated {
        hash: HashAlgorithm,
        salt: [u8; 8],
        hash_bytes: u32,
    },
    Salted {
        hash: HashAlgorithm,
        salt: [u8; 8],
    },
    Simple {
        hash: HashAlgorithm,
    },
    Private {
        tag: u8,
        parameters: Option<Box<[u8]>>,
    },
    Unknown {
        tag: u8,
        parameters: Option<Box<[u8]>>,
    },
}

String-to-Key (S2K) specifiers.

String-to-key (S2K) specifiers are used to convert password strings into symmetric-key encryption/decryption keys. See Section 3.7 of RFC 4880. This is used to encrypt messages with a password (see SKESK), and to protect secret keys (see key::Encrypted).

Note: This enum cannot be exhaustively matched to allow future extensions.

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

Iterated

Repeatently hashes the password with a public salt value.

Fields of Iterated

hash: HashAlgorithm

Hash used for key derivation.

salt: [u8; 8]

Public salt value mixed into the password.

hash_bytes: u32

Number of bytes to hash.

This parameter increases the workload for an attacker doing a dictionary attack. Note that not all values are representable. See S2K::new_iterated.

Salted

👎 Deprecated:

Use S2K::Iterated.

Hashes the password with a public salt value.

This mechanism does not use iteration to increase the time it takes to derive the key from the password. This makes dictionary attacks more feasible. Do not use this variant.

Fields of Salted

hash: HashAlgorithm

👎 Deprecated:

Use S2K::Iterated.

Hash used for key derivation.

salt: [u8; 8]

👎 Deprecated:

Use S2K::Iterated.

Public salt value mixed into the password.

Simple

👎 Deprecated:

Use S2K::Iterated.

Simply hashes the password.

This mechanism uses neither iteration to increase the time it takes to derive the key from the password nor does it salt the password. This makes dictionary attacks more feasible.

This mechanism has been deprecated in RFC 4880. Do not use this variant.

Fields of Simple

hash: HashAlgorithm

👎 Deprecated:

Use S2K::Iterated.

Hash used for key derivation.

Private

Private S2K algorithm.

Fields of Private

tag: u8

Tag identifying the private algorithm.

Tags 100 to 110 are reserved for private use.

parameters: Option<Box<[u8]>>

The parameters for the private algorithm.

This is optional, because when we parse a packet containing an unknown S2K algorithm, we do not know how many octets to attribute to the S2K’s parameters. In this case, parameters is set to None. Note that the information is not lost, but stored in the packet. If the packet is serialized again, it is written out.

Unknown

Unknown S2K algorithm.

Fields of Unknown

tag: u8

Tag identifying the unknown algorithm.

parameters: Option<Box<[u8]>>

The parameters for the unknown algorithm.

This is optional, because when we parse a packet containing an unknown S2K algorithm, we do not know how many octets to attribute to the S2K’s parameters. In this case, parameters is set to None. Note that the information is not lost, but stored in the packet. If the packet is serialized again, it is written out.

Implementations

impl S2K

pub fn new_iterated(hash: HashAlgorithm, approx_hash_bytes: u32) -> Result<Self>

Creates a new iterated S2K object.

Usually, you should use S2Ks Default implementation to create S2K objects with sane default parameters. The parameters are chosen with contemporary machines in mind, and should also be usable on lower-end devices like smart phones.

Using this method, you can tune the parameters for embedded devices. Note, however, that this also decreases the work factor for attackers doing dictionary attacks.

pub fn derive_key(
    &self,
    password: &Password,
    key_size: usize
) -> Result<SessionKey>

Derives a key of the given size from a password.

pub fn is_supported(&self) -> bool

Returns whether this S2K mechanism is supported.

Trait Implementations

impl Clone for S2K

fn clone(&self) -> S2K

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for S2K

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for S2K

fn default() -> Self

Returns the “default value” for a type.

impl Display for S2K

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Hash for S2K

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H) where
    H: Hasher, 

Feeds a slice of this type into the given Hasher.

impl Marshal for S2K

fn serialize(&self, w: &mut dyn Write) -> Result<()>

Writes a serialized version of the object to o.

fn export(&self, o: &mut dyn Write) -> Result<()>

Exports a serialized version of the object to o.

impl MarshalInto for S2K

fn serialized_len(&self) -> usize

Computes the maximal length of the serialized representation.

fn serialize_into(&self, buf: &mut [u8]) -> Result<usize>

Serializes into the given buffer.

fn to_vec(&self) -> Result<Vec<u8>>

Serializes the packet to a vector.

fn export_into(&self, buf: &mut [u8]) -> Result<usize>

Exports into the given buffer.

fn export_to_vec(&self) -> Result<Vec<u8>>

Exports to a vector.

impl<'a> Parse<'a, S2K> for S2K

fn from_reader<R: 'a + Read + Send + Sync>(reader: R) -> Result<Self>

Reads an S2K from reader.

fn from_file<P: AsRef<Path>>(path: P) -> Result<T>

Reads from the given file.

fn from_bytes<D: AsRef<[u8]> + ?Sized + Send + Sync>(data: &'a D) -> Result<T>

Reads from the given slice.

impl PartialEq<S2K> for S2K

fn eq(&self, other: &S2K) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &S2K) -> bool

This method tests for !=.

impl Eq for S2K

impl StructuralEq for S2K

impl StructuralPartialEq for S2K